US3789198A - Vehicle location monitoring system - Google Patents

Vehicle location monitoring system Download PDF

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US3789198A
US3789198A US00242349A US3789198DA US3789198A US 3789198 A US3789198 A US 3789198A US 00242349 A US00242349 A US 00242349A US 3789198D A US3789198D A US 3789198DA US 3789198 A US3789198 A US 3789198A
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vehicle
location
storage means
coordinates
heading
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A Henson
R Lewis
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Boeing Co
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Boeing Co
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01C—MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY
    • G01C21/00—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00
    • G01C21/26—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network
    • G01C21/28—Navigation; Navigational instruments not provided for in groups G01C1/00 - G01C19/00 specially adapted for navigation in a road network with correlation of data from several navigational instruments
    • G01C21/30—Map- or contour-matching
    • G—PHYSICS
    • G08—SIGNALLING
    • G08G—TRAFFIC CONTROL SYSTEMS
    • G08G1/00—Traffic control systems for road vehicles
    • G08G1/123—Traffic control systems for road vehicles indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, trams
    • G08G1/127—Traffic control systems for road vehicles indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, trams to a central station ; Indicators in a central station
    • G08G1/13—Traffic control systems for road vehicles indicating the position of vehicles, e.g. scheduled vehicles; Managing passenger vehicles circulating according to a fixed timetable, e.g. buses, trains, trams to a central station ; Indicators in a central station the indicator being in the form of a map

Definitions

  • the improved system includes a distance sensor, such as a counter storing revolutions of the vehicles odometer, and a heading sensor, such as a magnetic compass, which are located in a vehicle.
  • a time-multiplex communications system provides for transmission of changes in distance and heading to a central location at periodic intervals. The location of each vehicle is stored in a computer, starting with an initial known position, and periodically updated thereby using the transmitted distance change and heading change information. If desired, the stored vehicle locations may be transmitted to a display unit.
  • the computer also periodically compares the stored location of each vehicle against an internally stored matrix corresponding to the known streets, roadways and alleyway of the area. If the vehicle location and road location do not match, the vehicle location is updated to correspond to the nearest street.
  • the dispatcher had more accurate information about the location of every police vehicle, it is entirely possible that, given the location of a particular emergency, the dispatcher could reduce response time by directing a police car from an adjacent sector into the area because of that police cars closer proximity to the emergency than that of the police car assigned to the sector. Also, the sector concept may be dispensed with and a more dynamic and responsive approach to police car utilization effected.
  • a replica of a map of the area is located in the police car and a corresponding replica is located in the dispatchers base station.
  • the location of the car is reported at the initiation of the police officer by the positioning of an appropriate device on the map replica in the police car.
  • the coordinates of this position are detected by appropriate means and transmitted via a radio channel to the base station, and the coordinate information is reproduced in the form of a marker upon the dispatchers map replica. If the data in the radio channel is multiplexed to permit sharing of the channel by a plurality of police cars, the efficiency of data transmission is obviously improved.
  • this type of system is still subject to the major drawback of the voice reporting method, in that a police officer must initiate the reporting function.
  • systems in the second category use the principle of dead reckoning for determination of location.
  • dead reckoning an initial position of the car is determined and transmitted to the central or base station. This determination may be made either manually by the police officer or automatically by a signalling device located at a convenient location, such as the police garage, which causes a code to be transmitted to the central location when the vehicle passes in the vicinity of the signalling device.
  • the instantaneous location thereof at some later point in time can be computed by knowing the distance the car has travelled and any direction or heading changes that have occurred between the time the vehicle passed the initial position and the time of measurement.
  • the difficulty with prior systems using the principle of dead reckoning is that distance and heading errors arising from the distance and heading sensors accumulated with time, so that the total locational error continues to increase. Errors also arise from the fact that continuous reporting of vehicle distance travelled and heading directon cannot be made if more than one vehicle is to use the same communications channel. In order for a dead reckoning system to be accurate, the location information must be continuously corrected.
  • the prior art systems have been disadvantageous in this process of correction. For example, a plurality of check points may be established within the area of operation. A stationary transmitter or other device at the check point then causes the vehicles communications system to transmit a known location code when it passes in the vicinity of the check point.
  • a distance sensor providing an output signal for every predetermined increment of vehicle travel
  • a heading sensor providing an.
  • a second storage means contains the coordinates of drivable surfaces in the area.
  • a comparator provides an ottput signal if the coordinates in said first storage means do not correspond to any coordinates in the second storage means, and an update means is responsive to the comparator output signal to change the coordinates in said first storage means to correspond with those in said second storage means of the nearest drivable surface.
  • the invention resides in a method for continuously monitoring the location of a vehicle within a predetermined area, in which a lastknown location of the vehicle is stored in terms of coordinates X Y An incremental distance AD travelled by the vehicle from the last-known location is measured, and the heading angle of the vehicles travel is also measured. A new location is periodically computed for the vehicle in terms of coordinates X Y according to relations X X,,,,, AD[cos(heading)] and Y Y AD[sin(heading)]. The coordinates X Y are then stored as the coordinates X Y for subsequent computations.
  • the coordinates X Y may be compared with a table of coordinate values X Y,, corresponding to the drivable surfaces in the area.
  • a criterion for error correction is that the vehicle remain on a drivable surface. Therefore, if the coordinates X Y do not correspond to any coordinates X Y, in the table, the table is searched to find coordinates X Y which are nearest to X and Y Then, the coordinates X Y, may be stored as the coordinates X Y and the monitoring process continued.
  • the invention is also embodied in a vehicle location monitoring system for determining at a central station the locations of a plurality of vehicles within a predetermined area.
  • This system includes a plurality of mobile units, one being associated with each vehicle and each including a distance sensor and a heading sensor.
  • a multiplexed communications system provides for transmission of distance sensor and heading sensor output signals from each of the mobile units to a central station. At the central station, the distance and heading sensor output signals are temporarily stored.
  • a first means stores the last-known location for each of the vehicles.
  • a computing means periodically computes a new location for each of the vehicles and stores the new location in the first 'storage means. This computing means operates upon the last-known location for each vehicle, and the distance and heading inforamtion contained in the distance and heading sensor output signals.
  • a second storage means is provided at the central station which stores the locations of drivable surfaces in the area. Means are provided for comparing the location of each vehicle in the first storage means with the locations of drivable surfaces in the second storage means. An output is provided when the location of any vehicle does not correspond to any location in the second storage means. Upon occurrence of this output signal, updating means changes the vehicle location in the first storage means to correspond to the location of the nearest drivable surface contained in the second storage means.
  • FIG. 1 is a block diagram of a mobile unit of the vehicle location monitoring system
  • FIG. 2 is a block diagram of a base station unit of the system
  • FIG. 3 is timing diagram illustrating how the system time-multiplexes vehicle location and other information
  • FIG. 4 is a flow chart illustrating a computer program for controlling a digital computer in the system on-line to determine the locations of the systems mobile units and to update locations to compensate for accumulated errors;
  • FIG. 5 is a reproduction of a computer printout illustrating a computer-stored matrix corresponding to the known street, roadways and alleyways of a typical metropolitan area;
  • FIG. 6 is a reproduction of a map of a metropolitan area on which an X-Y plotter has traced the route of a vehicle whose location is computed using dead reckoning without compensation for accumulated errors;
  • FIG. 7 is a reproduction of the same map as in FIG. 6, with the same route being traversed by the vehicle, but with dead reckoning location information being updated by the technique of this invention;
  • FIG. 8 is a pictorial diagram illustrating a typical distance sensor for use with the invention.
  • FIG. 8A is a pictorial diagram illustrating a preferred distance sensor
  • FIG. 9 is a pictorial diagram illustrating a typical heading sensor for use with the invention.
  • Heading is typically defined as the angle of travel with respect to the earths north-south axis.
  • heading may be arbitrarily defined as the angle of travel with respect to a Y-axis established for the area, which may or which may not correspond with the earth s magnetic axis.
  • the Y-axis may be arbitrarily defined to coincide with a vertical axis of a map of the geographical area under consideration and the X-axis arbitrarily chosen to be perpendicular thereto.
  • Errors in the determination of the observers new location may arise from a number of sources.
  • First, the distance and heading measurements are made with some error. Although these errors may well be within a prescribed accuracy for the first determination of location, they generally accumulate as the second and succeeding location determinations are made by using the previously determined coordinates X Y as coordinates X Y in equations I and II. That is, the errors made in the first determination are added to those made in the second, the total errors in the second to those in the third, and so forth, so that the total location error after a given travel of the observer exceeds the prescribed accuracy. Second, equations 1 and II are valid only if the distance travelled AD is at a constant heading. In practice, the heading of the observer continuously varies in small amounts and occasionally in large amounts. If the calculations as described above are not made for every change of heading, an additional error is introduced which is also cumulative.
  • distance measurements are provided by revolution detector 10 which receives its input from a rotational mechanism of the vehicle which rotates in response to vehicle movement, for example, the vehicles odometer cable orits drive shaft.
  • an embodiment of the revolution detector 10 for sensing revolutions of the vehicles odometer cable includes a housing 103 having an input cable connector 102.
  • a cable from the vehicles differential or. transmission for the vehicle s odometer is coupled to a connector 102 by a cable connector 1111.
  • a shaft 104 rotates with a detector in response to vehicle movement.
  • Shaft 104 supports thereon a chopper disc 105 having a slit 106.
  • a light source 107 which is energized from a DC battery 108 is disposed on one side of the chopper disc 105, and a photoelectric detector 109 is disposed on the other side and provides an output pulse on a line 1 1 for every revolution of the shaft 104.
  • the output revolution connection to the vehicles odometer is completed by a connector 110, a cable connector 111, and an odometer cable 112.
  • a preferred embodiment of the revolution detector 11 which is not subject to errors arising from wheel spinning when the vehicle is stuck or driven on a slick street is seen in FIG. 8A.
  • a stationary shaft 113 such as a vehicles front axle, supports for rotation an undriven and freely rotating wheel 114, which may correspond to a front wheel of most American vehicles.
  • a disc is connected to and rotatable on shaft 113 with wheel 114i and includes a plurality of evenly spaced tooth-like projections 115A around its circumference.
  • disc 115 is of a magnetically permeable material so that the projections 115A interact with an adjacent, fixed magnetic sensor 1 16 to produce an output pulse on line 1 1 for every passage of a projection 115A.
  • Each pulse appearing on line 11 corresponds to a predetermined increment of vehicle travel.
  • the pulses are counted down by a divider 16 so that the output pulses therefrom on a line 17 correspond to larger increments of vehicle travel sufficient for system accuracy.
  • the pulses on line 17 may be pro vided for every 44 feet of vehicle travel.
  • These pulses are accumulated in a resettable counter 18 which provides an output on line 19 in a manner to be described hereinafter.
  • counter 18 may comprise a two-stage counter which is reset by a pulse appearing on a line 36A.
  • Heading measurements are made from the output of a heading detector 12 which includes a compass or other direction-sensitive element mounted on the vehicle.
  • a flux gate or magnetic compass may be used.
  • One embodiment of heading detector 12 is seen in FIG. 9 and includes a compass card 120 which is supported on pivots 121, 121A for rotation with the earths magnetic field.
  • a light source 123 which is powered from a DC battery 124 is positioned immediately above compass card 120.
  • a sector 122 is removed from card 120, allowing light transmission to certain ones of a plurality of photoelectric elements 125 which are arranged about the circumference of card 120.
  • the angles between the photoelectric elements 125 are all equal and each angle is in turn equal to the included angle of sector 122. Therefore, output signals are provided from those of photoelectric elements 125 which are actuated from light source 123 through sector 122.
  • the output signals indicate the relative orientation of the vehicle with respect to the earths magnetic axis.
  • the output lines from photoelectric elements 125, collectively designated 13 in FIG. 1, are coupled to the input of an encoding matrix 20 which may be of any type known to the prior art for converting the output signals thereon into an output pulse or pulse train under control of clock pulses on a line 35.
  • the inclued angle of sector 122 may be 22.5 degrees with the angle of separation between photoelectric elements 125 also being 22.5 degrees, and with sixteen photoelectric elements 125 being provided.
  • the vehicle location monitoring system may also include provision for transmission of the well-known ten" codes.
  • the system includes a keyboard 14 which may include at least ten push-button switches, not illustrated, for allowing an operator to enter the appropriate code in digit form.
  • the output lines of the switches in keyboard 14, collectively designated 15 in FIG. 1, are coupled to an encoding matrix 22 which is of a type for providing a pulse output corresponding to the selected code under control of clock pulses on line 35.
  • the signals on line 23 may be in the well-known binary coded decimal (BCD) code.
  • BCD binary coded decimal
  • Lines 19, 21 and 23 are connected to the input of a multiplexer 24 which provides an output pulse train on line 25 embodying distance, heading and ten code information at a time controlled by a gating signal obtained on a line 36A, tobe described hereinafter.
  • the pulse train signal on line 25 is modulated onto an appropriate rf carrier in an rf transmitter 26.
  • the rf signal appears on line 27 and is coupled to an antenna 28A by an antenna coupler 28.
  • the transmitted rf signal is received by an antenna 40 and coupled through an antenna coupler 42 and a line 43 to the input of a receiver 50.
  • the rf carrier is removed in receiver 50 and the modulated pulse train is provided via an output line 51 to a data converter 52, which converts the pulse train into a format suitable for a digital computer 54.
  • the converted data is transmitted on line 53 to a demultiplexer 54A, where it is demultiplexed, and then applied to a portion of a computer 54 operating under control of a program more fully decribed hereinafter.
  • Master clock 48 provides a plurality of clock pulses on a line 49C to computer 54 and demultiplexer 54A to establish a system time base. Included in master clock 48 is a counter 49A which counts the clock pulses and provides an output sync pulse of predetermined duration on a line 498 for every predetermined number of clock pulses. The sync pulse is used to establish a reporting cycle for the system and a typical rate thereof may be 1 Hz. Master clock 48 also includes circuitry, not illustrated, for developing an enable pulse from the sync pulse which is provided on a line 49 to the receiver 50 for controlling the operation thereof.
  • Each sync pulse on line 49B is applied to computer 54 and demultiplexer 54A for synchronizing, demultiplexing and reading operations, and to a signature generator 46 which is included in an rf transmitter 44.
  • the transmitters rf signal output is coupled via line 45 and antenna coupler 42 to antenna 40.
  • the signature generator 46 may comprise an oscillator providing a series of low frequency pulses for the duration of the sync pulse on line 49B. These pulses, or the signature, are modulated onto an if carrier by transmitter 44 and transmitted to each of the mobile units of the system.
  • the Signature pulses are used to synchronize the timemultiplexing operations of the mobile units with that of the base station unit illustrated in FIG. 2.
  • rf signals which are received by antenna 28A are coupled through antenna coupler 28 and a line 29 to the input of an rf receiver 30.
  • the rf carrier is removed in receiver 30 and the demodulated output appears on a line 31.
  • a signature detector 32 detects low frequency signature pulses on line 31 and provides a sync pulse on a line 33 which controls receiver 30-and which additionally enables and synchronizes a local clock 34.
  • the clock pulses from local clock 34 control the development of data signals and the time multiplexing of those data signals in the mobile unit.
  • the repetition rate of the clock pulses is identical to that of master clock 48.
  • Line 35 is connected to encoding matrix 20, encoding matrix 22, multiplexer 24, and a counter 36.
  • An output pulse is provided by counter 36 on a line 36A for every predetermined number of clock pulses on line 35.
  • Counter 36 is designed so that one output pulse is in every reporting cycle.
  • receiver 30 is additionally controlled by a control pulse provided by multiplexer 24 on a line 24A.
  • FIGS. 1 and 2 Additional structural details and operational features can be understood by considering FIGS. 1 and 2 in conjunction with the timing diagram illustrated in FIG. 3.
  • counter 49A provides an output to develop the sync pulse, seen in waveform 3(a), on line 49B.
  • the leading edge of the sync pulse enables the signature generator 46 which provides a low frequency pulse train until disabled at the trailing edge of the sync pulse, as seen in waveform 3(b).
  • the signature may comprise five output pulses at a l KHZ rate.
  • the trailing edge of the sync pulse also resets a counter and logic means, not shown, within demultiplexer 54A and is used by circuitry within master clock 48, not illustrated, to develop the enable pulse on line 49 which turns base station receiver 50 on, as best seen in waveform 3(d), for reception of multiplexed data from the plurality of mobile units used in the system.
  • the counter and logic means within demultiplexer 54A After resetting by the sync pulse, the counter and logic means within demultiplexer 54A provides a set of output signals from the clock pulses on line 49C which establish successive reporting intervals or time windows within each reporting cycle for recognizing the data transmitted from each of n mobile units during its assigned reporting interval, as best seen in waveform 3(e). For example, each interval may be 5 ms long.
  • the computer 54 is programmed to transfer the received and demultiplexed data to storage positions corresponding to each mobile unit.
  • the demultiplexer 54A transmits a reset pulse on line 57 to master clock 48 which in turn resets the counter 49A.
  • the enable pulse is removed from line 49 so that receiver 50 is temporarily disabled.
  • counter 49A again produces the sync pulse on line 493 to repeat the reporting cycle.
  • the signature detector 32 provides the output sync pulse on line 33 which is similar to the base station sync pulse illustrated in waveform 3(a).
  • the trailing edge of this sync pulse starts local clock 34 and disables receiver 30, as seen in waveform 3(0).
  • the clock pulses on line 35 are used to develop output signals on'lines 21 and 23,. which output signals correspond to the instantaneous heading of the vehicle and a desired ten code, if any.
  • counter 36 After a predetermined number of the clock pulses on line 35, counter 36 provides an output pulse on line 36A whose leading edge denotes the beginning of a particular reporting interval assigned to the mobile unit.
  • the mobile units reporting interval substantially coincides with one of the base stations reporting intervals because of synchronization effected by the signature pulses.
  • multiplexer 24 develops the output pulse train or information word on line 25 from the output signals present on lines 19, 211 and 23.
  • An example of a typical pulse train is seen in waveform 30'), and comprises the serial transmission of heading, AD, emergency status, noise guard, and two BCD numbers corresponding to a desired ten code.
  • the AD data only two bit positions in the pulse train are required for. the AD data. If the reporting cycle frequency is 1 Hz, and reporting is made once per cycle, then data transmission occurs at one-second intervals. Assuming that an output pulse is provided on line 17 from divider 16 for every 44 feet of vehicle travel, then counter 18 contains a 00 if the vehicle is stationary or travelling slower than 44 feet per second during the reporting cycle, a 01 if the vehicle is moving faster than 44 feet per second, a if the vehicle is moving faster than 88 feet per second, or a l 1 if the vehicle is moving faster than 132 feet per second and slower than 176 feet per second. Therefore, with a twobit code, vehicle speeds up to 176 feet per second, or mph, can be accommodated.
  • counter 18 At the trailing edge of the pulse on line 36A, counter 18 is reset to accumulate pulses on line 17 during the next reporting cycle.
  • multiplexer 24 provides a control pulse on line 24A to enable receiver 30 for reception of signature pulses to start a new reporting cycle.
  • the data converter 52 When the data from a plurality of vehicle units are received at the base station, the data converter 52 changes the data format from serial to parallel for operation upon by computer 54. The data is then demultiplexed by demultiplexer 54A as described previously and transferred to appropriate storage positions within computer 54.
  • the ten code data may be transferred to an appropriate display, not illustrated, which forms no part of the present invention.
  • the computer 54 is controlled by a program whose flow chart may be seen in FIG. 4.
  • a first memory array is established within computer 54 for storing the calculated X and Y coordinates of each mobile unit in the system.
  • the initial location having coordinates X of each vehicle is entered into this first array when the vehicle is about to leave a known position, such as the police garage.
  • the AD and heading data for the mobile units is entered into computer 54 under control of master clock 48A as aforesaid.
  • the X and Y coordinates in the first memory array are then changed for each mobile unit, preferably once a reporting cycle, by computing new coordinates X Y according to equations I and I! previously described, using the previous X and Y coordinates in the first memory array, and the AD and heading values for each mobile unit, and storing X Y in the first memory array.
  • the coordinates X Y may be transmitted by the computer 54 on line 55 to a display 56 which forms no part of the present invention but which may comprise a cathode ray tube for indicating instantaneous vehicle location on a map overlay.
  • a control section 58 within display 56 provides signals on line 59 for determining whether all or selected vehicle locations will be displayed.
  • a clock 54B internal .to computer 54 gates on an update subroutine at regular intervals, on the order of every 5 seconds.
  • Clock 5413 may be asynchronous with master clock 48.
  • Location correction in the update subroutine is based on a comparison of the calculated vehicle location contained in the first memory array with location information in terms of coordinates X Y located in a second memory array within computer 54 which corresponds to an areas known drivable surfaces, including streets, roadways and alleyways.
  • a map of a metropolitan area may be overlaid with a grid network having regularly spaced grid increments, with the X and Y axes being identical to those used for location reporting.
  • the X and Y coordinates of each grid intersection are assigned to specific positions in the second memory array. If the grid intersection coincides with a street, roadway or alleyway, a logic 1 is stored at the position in the second memory array corresponding to the X-Y coordinates of the grid intersection. If the grid intersection does not overlay a street, roadway, or alleyway, a logic is stored in the corresponding second memory array position.
  • FIG. 5 A simulated computer printout of the information stored in the second memory array for a portion of a given metropolitan area is illustrated in FIG. 5, where the dots correspond to logic ls and the blank spaces correspond to logic Os of the array.
  • the portion illustrated in F IG. corresponds to the upper portion of the map reproduction in FIGS. 6 and 7, including the area between streets 80 and 82.
  • the position of the street has been shifted in the second array to correspond with actual grid intersections, as the grid network cannot readily accommodate drivable surfaces consistently running at an angle other than parallel to grid lines or at 45 with respect thereto, and still maintain required accuracy.
  • the curved street is represented in the second memory array only at every other grid intersection.
  • Correction for cumulative errors is made by requiring the vehicle to remain on a drivable surface whose location X Y, is stored in the second memory array, and by moving the reported location X Y of a vehicle to an adjacent drivable surface X Y,,,. if the two locations do not coincide.
  • the second memory array is interrogated at the position therein corresponding to the last reported X and Y coordinates X Y of the vehicle. If that array position contains a logic 1, the vehicle location is defined to correspond to a known drivable surface, and no correction is made.
  • the second memory array is then searched in the direction perpendicular to the vehicles heading at two grid points from the calculated position and the array position first interrogated. If either of these grid points contains a logic 1, the X-Y coordinates X Y in the first memory array are changed to correspond to those X Y of either new position in the second memory array.
  • FIG. 6 was prepared by tracing the output of an X-Y plotter serving as display 56 upon a map of the metropolitan area.
  • the actual route that was travelled by a vehicle along a prescribed path to and from an initial location having coordinates X Y is shown by arrows.
  • the calulated location of the vehicle, without correction for cumulative errors, is shown by a bold line.
  • the vehicle travels at a constant heading 100.
  • the accumulated distance and heading errors cause the calculated location to depart from the actual route and off a drivable surface.
  • This location error thereafter accumulates until, at point 102, the vehicle is reported to be a full block away from the actual route. At the end of the route, the vehicle is reported at point 104 which is approximately a full block away from coordinates X Y In FIG. 7, the vehicle location is corrected for cumulative errors using the invention.
  • the vehicle travel is again reported at a constant heading At point 101, the reported location leaves the actual route as before.
  • the update subroutine in the computer 54 immediately returns the reported location to the route of travel. As a result of the update subroutine, the reported vehicle location remains on the actual route of travel, or close thereto, for the remainder of the traverse.
  • points 102 and 104 correspond exactly with the street of travel and with the starting and ending point X Y
  • a l 10-foot grid increment has been found sufficient for usein most metropolitan areas, inasmuch as the typical city block is 330 feet by 660 feet.
  • the maximum error in position reporting obtainable with this system is plus or minus 55 feet.
  • the error obtainable in a simple traverse without updating may amount to an entire city block, or 660 feet, particularly with reference to point 102.
  • An apparatus for continuously monitoring the location of a vehicle within a predetermined area including:
  • a distance sensor providing an output signal for every predetermined increment of vehicle travel
  • comparator means connected to said first and second storage means for comparing the coordinates contained in said first and second storage means and for providing an output signal if the coordinates in said first storage means do not correspond to any in said second storage means
  • an update means responsive to the output signal of said comparator means to change the coordinates in said first storage means to correspond with those in said second storage means of the nearest drivable surface.
  • a method for continuously monitoring the location of a drivable vehicle within a predetermined geographical area comprising the steps of:
  • steps (e)- (g) are repeated at periodic intervals.
  • a vehicle location monitoring system for determining at a central station the locations of a plurality of vehicles within a predetermined area, comprising:
  • c. at the central station means temporarily storing said distance and heading sensor output signals from said plurality of mobile units, a first means for storing a last-known location for each of said vehicles, means periodically computing a new location for each of'said vehicles and storing the new locations in said first storage means, said computing means utilizing the locations previously stored in said first storage means and said distance and heading sensor output signals, second means for storing the locations of drivable surfaces in the area, means for comparing the location of each vehicle in said first storage means with the locations of drivable surfaces in said second storage means, and providing an output when the location of any vehicle does not correspond to a location in said second storage means, and updating means responsive to said output for changing the vehicle in said first storage means to the location of the nearest drivable surface in said second storage means.
  • a vehicle location monitoring system as recited in claim 111 wherein said multiplexed communications system includes, at the central station, a master clock providing a plurality of clock pulses, means coupled to said master clock for periodically providing a synchronization pulse to establish a reporting cycle, means transmitting said synchronization pulse to said plurality of mobile units and a demultiplexing means having said clock pulses and synchronization pulses applied thereto for establishing a plurality of successive reporting inter vals during each reporting cycle to recognize the distance and heading output signals of each of said mobile units; at each of said mobile units, a multiplexing means responsive to said synchronization pulse for transmitting said distance and heading output signals to the cental station during a reporting interval assigned to the mobile unit.

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  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
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Cited By (49)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4024493A (en) * 1974-06-07 1977-05-17 Ingels George W Apparatus for motor vehicle position indication
US4032758A (en) * 1975-11-05 1977-06-28 The Boeing Company Compensated vehicle heading system
US4041285A (en) * 1976-04-12 1977-08-09 Pentron Industries, Inc. Bi-directional motion sensing and clocking system
US4055750A (en) * 1976-06-07 1977-10-25 Rca Corporation Heading sensor for vehicle dead reckoning system
US4061995A (en) * 1975-01-23 1977-12-06 Mccrickerd John T Odograph and heading indicator therefor
US4068307A (en) * 1976-05-06 1978-01-10 David Floyd Mile post location display system
US4084241A (en) * 1974-10-19 1978-04-11 Toshihiro Tsumura System for processing movement information of vehicle
US4224596A (en) * 1975-03-21 1980-09-23 Knickel Elwyn R Object locator system employing variable frequency code tone generators
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US10713860B2 (en) 2011-03-31 2020-07-14 United Parcel Service Of America, Inc. Segmenting operational data
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US4061995A (en) * 1975-01-23 1977-12-06 Mccrickerd John T Odograph and heading indicator therefor
US4224596A (en) * 1975-03-21 1980-09-23 Knickel Elwyn R Object locator system employing variable frequency code tone generators
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US4055750A (en) * 1976-06-07 1977-10-25 Rca Corporation Heading sensor for vehicle dead reckoning system
EP0011324B1 (en) * 1978-11-03 1983-03-02 THE PROCTER & GAMBLE COMPANY Fluidized bed process for making beverage, food or the like
EP0021060B1 (de) * 1979-06-11 1983-01-26 Siemens Aktiengesellschaft Leitsystem für den Individualverkehr
EP0025016A1 (de) * 1979-08-24 1981-03-11 Ascom Autophon Ag Einrichtung an einem auf einer Linie verkehrenden Fahrzeug zur drahtlosen Übermittlung von seinen Standort betreffenden Daten
US4403291A (en) * 1979-10-11 1983-09-06 Siemens Aktiengesellschaft Self-sufficient navigation device for street vehicles
US4402050A (en) * 1979-11-24 1983-08-30 Honda Giken Kogyo Kabushiki Kaisha Apparatus for visually indicating continuous travel route of a vehicle
US4435760A (en) 1980-02-08 1984-03-06 Nippon Soken, Inc. Running position indicator apparatus
EP0036119A1 (fr) * 1980-03-06 1981-09-23 Patrice Bernard Système de localisation d'un véhicule
FR2477740A1 (fr) * 1980-03-06 1981-09-11 Bernard Patrice Systeme de localisation d'un vehicule
US4388608A (en) * 1980-03-06 1983-06-14 Patrice Bernard Vehicle location monitoring system
US4357833A (en) * 1980-09-02 1982-11-09 Aga Aktiebolag Position determination equipment
US4484192A (en) * 1981-12-17 1984-11-20 The Bendix Corporation Moving map display
US4660037A (en) * 1982-01-28 1987-04-21 Honda Giken Kogyo Kabushiki Kaisha Current location indication apparatus for use in an automotive vehicle
US4646089A (en) * 1983-01-17 1987-02-24 Nippondenso Co., Ltd. Travel guidance system for vehicles
EP0166547A3 (en) * 1984-06-07 1989-03-08 Etak, Inc. Vehicle navigational system and method
AU587982B2 (en) * 1984-06-07 1989-09-07 Tele Atlas North America, Inc. Vehicle navigational apparatus and method
JPH0830657B2 (ja) 1984-06-07 1996-03-27 エタック インコーポレーテッド 車両ナビゲーション装置
US4922447A (en) * 1985-10-09 1990-05-01 Alcatel N.V. Device for measuring the distance travelled and the speed of a rail vehicle
EP0261404B1 (de) * 1986-09-25 1991-02-13 Siemens Aktiengesellschaft Navigationseinrichtung für ein Fahrzeug
US4807127A (en) * 1986-12-10 1989-02-21 Sumitomo Electric Industries, Ltd. Vehicle location detecting system
EP0276366A1 (de) * 1986-12-17 1988-08-03 Robert Bosch Gmbh Korrekturverfahren für die Koppelortung von Landfahrzeugen
EP0346906A3 (en) * 1988-06-16 1991-05-29 Nissan Motor Co., Ltd. System for displaying the present position of a moving object
US5155688A (en) * 1989-10-24 1992-10-13 Mitsubishi Denki Kabushiki Kaisha Vehicle navigation system
EP0494499A3 (en) * 1990-12-21 1992-09-23 Rockwell International Corporation System and method for monitoring and reporting out-of-route mileage for long haul trucks
US5548822A (en) * 1993-06-15 1996-08-20 Aisin Seiki Kabushiki Kaisha Mobile station monitoring system
WO1995018432A1 (en) * 1993-12-30 1995-07-06 Concord, Inc. Field navigation system
US5684476A (en) * 1993-12-30 1997-11-04 Concord, Inc. Field navigation system
US5955973A (en) * 1993-12-30 1999-09-21 Concord, Inc. Field navigation system
US5862511A (en) * 1995-12-28 1999-01-19 Magellan Dis, Inc. Vehicle navigation system and method
US5991692A (en) * 1995-12-28 1999-11-23 Magellan Dis, Inc. Zero motion detection system for improved vehicle navigation system
US6029111A (en) * 1995-12-28 2000-02-22 Magellan Dis, Inc. Vehicle navigation system and method using GPS velocities
US5948043A (en) * 1996-11-08 1999-09-07 Etak, Inc. Navigation system using GPS data
DE19701683A1 (de) * 1997-01-20 1998-07-23 Plath Naut Elektron Tech Peilempfänger für den Einsatz in TDMA-Netzen
US6232889B1 (en) * 1999-08-05 2001-05-15 Peter Apitz System and method for signal light preemption and vehicle tracking
US6477465B1 (en) * 1999-11-29 2002-11-05 American Gnc Corporation Vehicle self-carried positioning method and system thereof
US6671622B2 (en) * 1999-11-29 2003-12-30 American Gnc Corporation Vehicle self-carried positioning method and system thereof
WO2003040751A1 (en) * 2001-11-09 2003-05-15 Bengtsson, Jan Method for monitoring the movements of individuals in and around buildings, rooms and the like, and direction transmitter for execution of the method and other applications
US20050035872A1 (en) * 2001-11-09 2005-02-17 Leif Nyfelt Method for monitoring the movements of individuals in and around buildings, rooms and the like, and direction transmitter for execution of the method and other applications
US7180414B2 (en) 2001-11-09 2007-02-20 Jan Bengtsson Method for monitoring the movements of individuals in and around buildings, rooms and the like, and direction transmitter for execution of the method and other applications
AU2002343305B2 (en) * 2001-11-09 2007-11-29 Bengtsson, Jan Method for monitoring the movements of individuals in and around buildings, rooms and the like, and direction transmitter for execution of the method and other applications
AU2002343305B9 (en) * 2001-11-09 2003-05-19 Bengtsson, Jan Method for monitoring the movements of individuals in and around buildings, rooms and the like, and direction transmitter for execution of the method and other applications
US20060080036A1 (en) * 2004-10-07 2006-04-13 General Motors Corporation Method for determining vehicle location
US8896430B2 (en) 2008-09-09 2014-11-25 United Parcel Service Of America, Inc. Systems and methods for utilizing telematics data to improve fleet management operations
US11482058B2 (en) 2008-09-09 2022-10-25 United Parcel Service Of America, Inc. Systems and methods for utilizing telematics data to improve fleet management operations
US10540830B2 (en) 2008-09-09 2020-01-21 United Parcel Service Of America, Inc. Systems and methods for utilizing telematics data to improve fleet management operations
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US20110153136A1 (en) * 2009-12-17 2011-06-23 Noel Wayne Anderson System and method for area coverage using sector decomposition
US20110153072A1 (en) * 2009-12-17 2011-06-23 Noel Wayne Anderson Enhanced visual landmark for localization
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US10713860B2 (en) 2011-03-31 2020-07-14 United Parcel Service Of America, Inc. Segmenting operational data
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FR2179709B1 (enrdf_load_stackoverflow) 1976-01-30
FR2179709A1 (enrdf_load_stackoverflow) 1973-11-23
GB1384940A (en) 1975-02-26

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